Discriminating circuit



Marsh 3, 1959 B. A. HARRIS DISCRIMINATING CIRCUIT 3 Sheets-Sheetk 1Filed Dec. 31, 1956 ATTORNE Vf B. A. HARRIS DISCRIMINATING CIRCUIT Marh3, 1959 Filed Deo. 31, 1956 1 u w bw\ n @N9 I IH 1 2o., NoIW o f \l wmow @Num mm., @6m Num uw March 3,` 1959 B. A. HARRIS DISCRIMINATINGCIRCUIT 5 sheets-shee Filed DBG. 31, 1956 Om., n DOmO Ehm-Umm my mwUnited States Patent() DISCRIMINATING CIRCUIT Ben A. Harris, Rochester,N. Y., assignor to General Dynamics Corporation, Rochester, N. Y., acorporation of Delaware Application December 31, 1956, Serial No.631,568

12 Claims. (Cl. 179-18) This invention relates to telephone systems andparticularly to signaling means for discriminating between incoming andoutgoing traihc over any given line.

rthe object of the invention is to provide means associated with a givencircuit which will, during the use thereof, indicate the direction inwhich the circuit is being used, and specifically, by way of example,whether the circuit is involved in an incoming or an outgoing call.

It is conventional in telephone systems to have a line circuit as partof each line, this circuit containing essentially a line relay whichwill signal an outgoing call from the line and a cut-off relay whichwill disconnect this line relay from the line when other properswitching arrangements have been made. Usually, on outgoing calls theoperation of the line relay serves to bring a line finder into operationwhich makes a connection to the calling line and extends it to aselector which may thereupon be selectively operated over the callingline. The line circuit also has terminals appearing in connectorswhereby incoming connections may be established to the line.

Immediately the line circuit has been seized on either an incoming callor an outgoing call, all terminals appearing in other locations must bemarked as busy and hence the private wire or the sleeve as it is knownwill be characterized by a busy potential. Thus, during the use of theline a single condition is established to denote a call, be it incomingor outgoing.

It is desirable to know the character of a call and hence the means ofthe present invention is provided to differentiate between the two kindsof call. In accordance with this means advantage is taken of a slightdiiference in the establishment of the call and this difference isemployed to register the character of the call. On an incoming call allthe sleeve terminals of the line, both those in the connector banks andthose in the line finder banks are immediately grounded with the resultthat a discriminating relay is prevented from operating. On an outgoingcall, however, the sleeve terminals in the connector banks areimmediately grounded but the like terminals in the line finder banks aretemporarily connected to battery as a condition for which the linefinder seeks. This interval is transitory as the finder may act veryquickly-yet brief as it may be the discriminating relay will operate andwill lock to the ground applied to the sleeve in the connector bank. Thedifference between an incoming call and an outgoing call is that thereis a transitory operation of the line relay on an outgoing call and someresult of this is translated into an indication of an outgoing call.

Thus during the existence of the call either an incoming or an outgoingsignal may be operated. This signal may take various forms, being eithera simple lamp signal or a register by which the number of incoming andnumber of outgoing calls may be toted up.

A feature of the invention is a discriminating relay means added to aline circuit for indicating the character of a call andl depending forits energization on a slight 2 delay in the extension of a busy signalto a certain terminal which invariably is marked as busy regardless ofthe character of a call, no such slight delay being present in a call ofa different character.

Another feature of the invention is the use of a discriminating relayoperated by a line calling condition and locked into operation by a linecalled condition. Where the call is an incoming call, that is the lineis playing the role of a called line, a line called condition is immediately placed on the line nder terminals` of the line, but where thecall is outgoing from the line, a line calling condition is placed onthe line finder terminals so that the finder may discover thisparticular line and extend it to a selector.

Another feature of the invention is a circuit having a line relay, acut-oif relay and a discriminating relay responsive inits initialoperation to the operation of said line relay and responsive in itscontinued operation to the continued operation of said cut-off relay.The dis- 4 criminating relay will only operate while the line relay isoperated, but after the discriminating relay has operated it depends forits continued energization on a circuit through a back contact of theline relay and a locking contact of the cut-off relay. Therefore it maybe stated that the discriminating relay follows the line relay and holdswith the cut-olf relay.

Another feature of the invention is a discriminating relay having twowindings, one of which is connected to one pole of a battery while therelay is unoperated but is switched to the other pole of the batterywhile the relay is operated and the other of which acts as a holdingwinding. A unique circuit arrangement resides in the connections wherebythe circuit of the holding winding is momentarily broken after the firstwinding is switched from one pole of the battery to the other so thatthis rst winding acts as a holding winding during that interval` inwhich the circuit of the holding winding is interrupted. Thus thediscriminating relay is provided with an energizing winding and aholding winding and has circuit changing means for causing theenergizing winding to act as a holding winding after its duties as ameans for energizing the relay have been completed and particularlyduring a following switching period in which the circuit of the holdingwinding is momentarily interrupted.

Another feature of the invention is the employment of a transitory timeinterval during the release of the line relay for making a circuitchange which spells the difference between an incoming and'an outgoingcall.

Thus on the establishment of an outgoing call where thel line relay hadbeen operated, the transfer of the connector sleeve circuit from oneground to another includes a transitory break and this break is employedto release a fast acting relay and to thus make a circuit change.

Two different embodiments of the present invention are shown in each ofwhich the transitory operation of the line relay is employed to registerthe call as outgoing rather than as incoming.

Further in accordance with the present invention the unique indicatingmeans of the present invention is shown as the essential element of atrafc recorder circuit whereby any given group of lines may be put underobservation and 'a continuing record of the condition of each made overan indenite period at very short intervals. In a preferred embodiment ofthe invention the condition of each line of a group is noted at tensecond intervals, and acomposite record taken of the number of incomingcalls and outgoing calls existing during any half hour period.

Other features will appear hereinafter.

The drawings consist of three sheets having seven figures, as follows:

Fig. 1 is a schematic circuit diagram indicating various components in atelephone system `and showing in detail a line circuit and itsconnections to the means for establishing incoming and outgging calls;

Fia 2 is t sito# diagram of a means whih may be conne ed to alinecircuit and which will indicate during a nse ot the associated line thenature of the call, i.l e. an incoming or an outgoing call;

Eig. is a diagram of asimilar circuit used for the samefpurpose, butinwhich the indication is produced in a i erenft manner;

. .1 4 is a'sherrratic circuit diagram of a selecting i' hich theseparate line circuits of a group may be suoceri/sly Scanned;

Pig. 5 is a`schernatic circuit diagram of a means to malgre a record ofwhat is found in a recording cycle and a means to control the saidscanning means;

Fig. 6 is a block diagram showing how the three sheets of drawings areto be placed to provide a complete sche ic circuit diagram of one formof the invention in winch Fig. 3 is used, and;

Eig. 7 is a block diagram show-ing how the same three sheets of drawingsare to be placed to provide a cornplete SClJelnatiC circuit diagram ofanother form of the invention in which Fig. 2 is used.

In a telephone system a subscriber at station 1 may establish aconnection to another subscriber by conventional rneans. By lifting histelephone from its cradle he place a bridge on his line and cause theoperation of the line relay 2. This will place a ground on the startwire 3:` to operate the allotter (not shown) which will start the linefinder 4 and which in time will pick up the calling line and extend theconnection to the selector 5, When the finder 4 seizes the calling linea ground will be returned over the sleeve S and this will befextended tothe cut-oit relay 6, tirst through a front Contact and armature. of theline relay 1 and immediately thereafter over a front contact andarmature of the cut-oij'relay itself. Upon the operation of the cut-oirelay '6 1, the line relay 2 will be released.

It' is` to be noted that in the interval between the operation` of theline relay 2 and the cut-off relay 6, afcircuit may be traced frombattery, the winding of the cutfol relay 6, an armature and frontcontact of the line relay 2, the vlower comparatively high resistancewinding of relay 7, a back contact and armature of this relay to groundwhich will result in the operation of this relay.

Also, upon the operation of the line relay the sleeve conductor SN ofthis line circuit extending into the connector bank terminals isgrounded by a front contact of theline relay s o that upon the operationof fast acting preliminary contact, marked X, of the relay 7 a holdingcircuit for relay 7 will be completed through its upper winding whichwill result in the very positive action of .ths'relar 'A YIt should benoted that upon the operation of the line relay 2 and the consequentgrounding of the sleeve SN condnctor, av circuit is* momentarilyestablished to the incoming TT wire 8 but it will be understood thatthis circuit is maintained for only a ileeting instant since the relay 7operates immediately and opens the circuit to thefwir'e 8l Instead, asolid connection will be made from ground, a lower armatureand frontContact of relay 7 tothe outgoing TO wire 9, so that as a result of anoutgoing call-made from thev substation 1, the outgoing wird? willbegrounded and this condition will be maintained for, the duration ofl thecall. Through the operation' of. the relay 7 a source of battery througharesistance 1,0l will be, connected to the lower winding of the relay 7lto hold this relay operated during the instant that groundiisA removedfrom the SN conductor as the line relay is releasing. Thus an outgoingcall fromthe station 1.,is...regiateredghy.I thef, groundirig ofl theT01` wire 9 in A nector 11, the SN sleeve conductor is grounded to causethe immediate operation of the cut-0E relay 6 and this ground is alsoextended through a front contact of this relay to the S sleeve conductorbut since in its unoperated condition the lower winding of relay 7 isalso connected to ground, this relay 7 will not operate. In this casethe incoming TT wire 8 will be grounded and thus an incoming call willbe registered by the grounding of the TT incoming lead.

Hence it appears that the relay 7 will discriminate between an outgoingcall and an incoming call, though during either such a call, both sleeveS and sleeve SN are grounded- The discrimination cornes through thePreliminary and transitory battery connection to the sleeve S during theline finding operation.

Fig. 3 shows another means for discriminating between an incoming calland an outgoing call, in which the incoming TT wire 1 2 or the outgoingTO wire 13 is grounded during a call. In this case the discrimination ismade, not byv taking advantage 0f the fleeting battery connection to theS lead but rather .by the fleeting re Inoval of ground from the SN leadas the line relay 2 releases after the operation of the cut oit relay 6.In accordance with this embodiment of the invention, the SN lead isimmediately grounded for any call, either incoming or outgoing.Thereupon a fast acting relay 14 is first operated through a backcontact of a slow release relay 15 and then locked to the ground on theSN lead independent of the relay 1S. The operation of the relay 14results in the operation of the relay 15 and the grounding of theincoming TT lead 12 and if both relays 14 and 15 are left in thiscondition the ground maintained on the lead 12 will lniark this as anincoming call.

However, if it isl in fact Van outgoing call, then the originalgrounding of the ySN lead would have resulted from the operation of theline relay 2 so that as the calling line is picked up by the line tinder4 and the cut ott relay 6 is operated, then the line relay 2 isreleased. During this operation the SN lead i s disconnected from groundfor a iieeting instant and within such time interval the fast relay 14will release, the slow releasing relay 15 holding operated. until itslocking circuit is completed through a back contact of relay 14. Withrelay 14 released and relay 15 operated, the outgoing TO conductor 13will become grounded to man( this as an outgoing call.

In both Figs. 2 and 3, at the termination of the call, either incomingor outgoing the operated relay or relays will be released. and groundremoved from the` incoming or the outgoing wire.

It may be noted that this indication of the nature of a Call may beemployed for any given purpose Lamps connectedfto the incoming TT leadsand the outgoing TO leads will provide a` visual indication. Anotherspeciiic employment ot thisindication i s disclosed in Figs. 4 and 5where a means Afor collecting traic data is shown. Fig. 4 shows a,selector whereby during` successive time intervals a, completegroup ofline circuits may be scanned so that a record of traic conditions maybemade. For the purpose ofV explaining the operation of the selector ofFig. 4 it will` be noted here that under given conditions whichwill beexplained morein detail hereinafter, the PL relay 16 inFig. 5 willjoperate over a cycle at the rate of 12D operations perminute, duringwhich a ground will be steadily `applied to conductor 17 andintermittently applied to conductor 18.

On the firstC application o iV ground to these two conductors a circuitwill be extended from conductor 18 and thencein a chain over armaturesand' back contacts of relays SA19 through. SA1 inclusive `to the windingof the SG1 relay 1,9. rThisV ground will then be also extendedQverafrout Contact. QttheSQl! relay 19 through aback contact/of` the SA1relay.d 20, the winding thereof Qrrtanincorningcallto.stationzl by wayof the conin a circuit which at this time is ineiective since the otherterminal of this winding is connected to ground over a back contact ofthe SA2 relay to ground on'the conductor 17, in a circuit such as thatextending from the winding of the SA19 relay 21 to a lower armature andback contact of the SA20 relay 22.

When the relay 16 releases and removes ground from the conductor 18,relay 19 remains operated in series with relay 20 and relay 2t) becomesoperated. As relay 20 operates it locks to battery on conductor 23 andopens the circuit of relay 19 which thereupon releases. Relay 20rearranges the circuit from conductor 18 so that when ground is nextapplied thereto the SC2 relay 24 will be operated.

It is to be noted that during the operation of the SCI relay, the T01conductor is connected to the outgoing line 25 and the TTI conductor isconnected to the incoming conductor 26. As the impulse over conductor 18comes to an end then the SCI relay is released as above described andthe connection of the conductors 25 and 26 to a rst line circuit isterminated. During the succeeding operation of the SC2 relay theseconductors are extended to a second line circuit and it is believed tothus be clear that the various line circuits of a group are successivelyextended to a recording circuit reached over these conductors 25 and 26.

It is to be noted that there is no overlapbetween the operation of suchrelays as the SCI relay 19 and the SC2 relay 24 so that no two linecircuits may be simultaneously connected to the recording circuit.

The SAI relay 20 is locked in a circuit including its own armature andfront contact and an armature and back contact of the next SA2 relay(not shown) so that when in turn the SA2 relay is operated, the SAlrelay 20 will be released to provide a circuit for the eventualoperation of the SA20 relay 22.

It will appear hereinafter, that when the SA20 relay 22 operates and theSC20 relay 27 releases at the end of a scanning operation a circuit willbe closed between conductors 28 and 29 to advance the operation of the`circuits as will shortly be explained.

Looking now at Fig. 5, it will be noted that a start key 30 is providedwhich upon operation will start a registering operation and through itslocked in continued operation will enable the circuit. This circuitconsists essentially of a rotary stepping switch having two sets oftwenty contacts each. The wipers 31 of level A are of the bridging typeand will move step by step over contacts 1 to 16 inclusive at the rateof one step every two minutes and thus complete one cycle of operationin thirty minutes. The wipers 32 of the nonbridging type move with thewipers 31. When the key 30 is operated the RB relay 34 will be operatedand will thereby connect the register 39 to the Wire 25 and the register40 to the wire 26 so that for a half hour the line circuits associatedwith this circuit may be scanned once each ten seconds. At the end ofthis operation a warning bell 37 will be sounded, whereupon an attendantwill operate the transfer key 38 to transfer from the B to the Aregisters so that during the next half hour the relay 33 will beoperated and the registers 3S and 36 will be connected to the wires 25and 26 respectively. During this time the attendant may take readingsfrom the registers 39 and 40 and reset them to zeroready for a newoperation.

When the start key 30 is operated a circuit is established from battery,the magnet 41 for the stepping switch, the lower operated contacts ofthe switch 30, the wiper 32 on its resting contact 20, the armatures andback contacts of the RA. relay 33 and the RB relay 34 to the lead 42over which one pulse every two minutes is delivered. On the first ofthese pulses the magnet 41 will be energized and when the pulse isterminated the wipers 31 and 32 will move to the number 1 contacts ofthe switch. In this position a ground is placed on wiper 31 from thewire 17 now grounded by the key 30, and this ground will be extended byway of the number 1 contact of level A of. the switch through the lowernormal contacts of the transfer key 38, an armature and back contact ofthe RA relay 33 to the winding of the RB relay 34 and thence to battery.Relay 34 operates and locks through its armature 45 and front contact tothe ground on wire 17.

As'the wipers of the switch move to their number 1 contacts the rotaryolf normal switch 43 operates and this connects the I. P. M. lead 44 tothe PL relay 16 so that the counting relays of Fig. 4 operate as in aring circuit completing a cycle each ten seconds.

Since the switch is moved forward under the control of its wiper 32connected to the lead 42 over which one ypulse is delivered every twominutes, it will take thirty minutes for the wiper to reach its contactnumber 16 and during this half hour the line circuit indications ofincoming and outgoing calls will'have been scanned 180 times whereby anaccurate determination of the trac conditions may be made and recordedon the registers 39 and 40.

Upon the movement of the wiper 32 on to the sixteenth contact of level Band thereafter upon the operation of the SA20 relay 22 and the releaseof the SC20 relay 27, a circuit will be completed from the switch magnet41, the operated contacts of the start key 30, wiper 32, its sixteenthcontact lead 28, a front contact of relay 22, and a back contact ofrelay 27, lead 29 to the switch contacts 17, 18 and 19 and thence to theback contact and armature of the switch magnet 32 whereby the switch isstarted on an automatic movement over its contacts 17, 18 and 19 to endup on its contact 20. During its travel over contacts 17, 18 and 19 thebridging wiper 31 will cause'a single operation of the scan counter 46.The

operation of the scan counter will cause the operation of the RA relay33, thus releasing the RB relay 34 and the registers 35 and 36 will beenabled, whereby the continued operation ofthe counting relays of Fig. 4and the stepping switch of Fig. 5 will now start the accumulation ofdata on the A registers. At this time, the operation of the RA relay 33will close a circuit for the alarm bell 37. The attendant will thereuponoperate the transfer key 38 to silence the bell 37, and prepare thecircuits for a similar response at the end, of this next thirty minuteperiod. It may be noted that the lamps 47 and 48 will give an indicationof which set of registers are in operation at any given time.

It is believed that with this explanation it will be clear how theswitch having wipers 31 and 32 will continuously operate over thirtyminute cycles and how at the end of each cycle the other s et ofregisters will be enabled and the alarm bell 37 operated. At this timethe operator will move the transfer key to its other position andproceed to record the readings of the registers which have justcompleted a cycle, and to reset them ready for a next cy'cle.

What is claimed is:

1. In a telephone system, a line circuit having a line relay, a cut-offrelay, and discriminating relay means for signalingvthe incoming oroutgoing nature of a call during the continued operation of said cut-olirelay, said discriminating relay means being responsive to an operationof said line relay, prior to an operation of said cut-off relay. v

2. In a telephone system, a line circuit for each of a plurality oflines therein, each said line circuit having a line relay responsive toan outgoing call from its said associated line and a cut-oli relayresponsive to both an outgoing and an incoming call to said associatedline and relay means responsive to an operation of said line relay priorto an operation of said cut-olf relay for signaling an outgoing callfrom said associated line.

3. In a telephone system, a line circuit having a line relay, a cut-olirelay and a discriminating relay, means controlled byv said line relayfor operating said discrimi- Hating relay and means Controlled, bv saidcutfot relay for holding said discriminating-relay.

4. In a telephone system, a, line circuit having aA linel relay, acut-ott relay and a discriminating relay, means controlled by said linerelay for operating Said discriminating relay, means controlled by said`cut-.0E relay fOr holding said discriminating relay and means controlledby said discriminating relay for indicating an outgoing call in whichsaid line relay is momentarily operated and for indicating an incomingcall in, which the operation of said line relay is prevented.

5. In a telephone system, a subscriber line circuit including a line, aline relay responsive to the initiation of an outgoing lcall and acut-ott relay for cutting ott said line relay from said line on eitheran incoming or an outgoing call, indicating means for signaling eitheran incoming or an outgoing call, discriminating relay means forcontrolling said indicating means, means controlledr by said line relayfor operating said discriminating relay means and means controlled bysaid cut-olf relay forv maintaining said established indication.

6. In a telephonesystem, a subscriber line circuit including a line, aline relay responsive to the initiation of, an outgoing call and acut-off relay for cutting Said line relay off said line on either anoutgoing or an incoming call, a discriminating relay for controllingmeans to indicate the incoming o r outgoing natur-e of a call, saiddiscriminating relay having a comparatively high resistance operatingwinding, a holding winding and switching means for providing a holdingcircuit through said operating winding for temporarily holding saiddiscriminating relay operated over a momentary break in the circuit ofsaid holding winding.

7. In a telephonev system, a line, a line circuit having a line relayresponsive to the initiation o f an outgoing call from said line and acut-oli relay for cutting said line relay off of said line responsive toeither an outgoing o1' an incoming call on said line, a bank of outgoingc all terminals for said line including a sleeve terminal, a bank ofincoming call'terminals for said line including a sleeve terminal, adiscriminating relay having an operating winding and a holding winding,Said operating winding being connected to Said outgoing sleeve terminaland said holding Winding being connected to said incoming sleeveterminal.

8. In a telephone system, a line, a line circuit having a line relayresponsive to the initiation o f an outgoing 4call from said line and acut-off relay for cutting said line relay olf of said line responsive toeither an outgoing or an incoming call on said line, a bank of outgoingcall terminals for said line including a sleeve terminal, a bank ofincoming Call terminals Afor said line including a sleeve terminal, adiscriminating relay having an operating winding and a holding Winding,said operating winding being connected to said outgoing sleeve terminaland said holding Winding being connected to said incoming sleeveterminal and means for indicating the outgoing or incoming nature of acall controlled by said discriminating relay.

9. In a telephone system, a line, a line circuit including a line relayresponsive to'the initiation of an outgoingcall from saidline and acut-off relay for cutting said line relay off oi said line responsive toeither anoutgoing or an incoming call on said line, a bank of outgoingcall terminals for said line including a sleeve terminal, a bank ofincoming call terminals for said line including a sleeve terminal, adiscriminating relay having a comparatively high resistance operatingwinding con nected to said outgoing sleeve terminal and a winding in aholding circuit connected to said incoming sleeve terminal, saidincoming sleeve terminal being connected to a transfer armature of saidline relay, having a front contact connected to a source of busypotential and a back contact connected to said cut-off relay and saidoutgoing sleeve terminal being connected to make contacts of both saidline and cut-.ott relays for connecting said outgoing sleevetermnal to.said eut-off relay- 10. In a telephone system, a line circuit having acutoff relay and a line relay, a private wire terminal con. trolled bysaid line relay, a discriminating circuit connected to said private Wireterminal including two relays, both said relays being responsive to aconnection made to said private uure and one of said relays beingthereafter responsive to a transitory interruption of said connectionand means for indicating either an incoming or an outgoing callresponsive to the concurrent operation of both said relays or thecontinued operation of but one of said relays respectively.

ll. In a telephone system, a line, a line circuit for said lineincluding a line relay transitorily response to an outgoing call fromsaid line and a cut-off relay continuously responsive during thecontinuance of either an incoming or an outgoing call from said line andmeans to indicate the nature of a call consisting of a pair of relaysboth responsive to the establishment of either an incoming or anoutgoing call and one of said relays being released by the release ofsaid line relay during the establishment of an outgoing call from saidline.

l2. In a telephone system, a plurality of telephone lines, a linecircuit for each said line including a line relay and a cut-off relay, adiscriminating circuit having an outgoing call lead and an incoming calllead, means responsive to the operation of said cut-olf relay forestablishing a given electrical condition on said leads, meansresponsive to a prior transitory operation of said line relay forconning the establishment of said given electrical condition to saidoutgoing call lead, a closed ring of counting relays for successivelyconnecting the said outgoing call leads and the Said incoming call leadsto a pair of recording leads and means for recording the number ofoutgoing calls and the number of incoming calls encountered in aplurality of operations of said ring circuit over a given time period.

References Cited n the file of this patent UNITED STATES PATENTS

